This invention relates to improvements surge voltage arresters for line protectors of the type used for protecting telephone lines and like communication lines from over-voltage and over-current conditions.
Surge voltage arrester of the cold cathode gas discharge tube type serve as the primary arrester and source of protection in various line protectors. Such line protectors may also include a carbon or other type of air gap back-up protector in the event of a failure of the primary surge arrester as a result of leakage of gas from the tube due to a broken seal or similar damage. A gas tube arrester which has failed in this manner will be difficult to detect because the line to which it is connected continues to operate properly. Thus, it is desirable to provide some type of air gap or secondary surge arrester as a "back-up" or vent safe feature in the event of failure of the gas tube arrester. Line protectors embodying these surge voltage arresters are frequently installed under conditions wherein dust, moisture and other contaminants can enter the secondary air gap. This can alter the breakdown voltage characteristics of the air gap and possibly reduce its reliability.